Providing lubricant to bearings can be important and challenging for many bearing applications. Bearing cages or bearing retainers represent such an application, in which balls or rollers are spaced along a cage or retainer structure and in which lubricant is contained in reservoirs between pockets for the balls or rollers, along the cage or retainer structure. A bearing apparatus may include inner and outer bearing races, balls, and such a cage/retainer that holds the balls or rollers.
An important function of some bearing cages or retainers is to store grease in areas between the pockets to provide lifetime lubrication. Oil bleeding from the grease migrates away from the reservoir and along the cage surfaces due to local capillary and surface forces. This oil in the pockets lubricates ball or roller surfaces through cage contact. Ensuring proper migration of this oil can be challenging. Inadequate migration may result in failures relating to bearing wear and grease degradation, due to insufficient lubricant supply in the race-ball (or roller) contact interfaces and frictional heating.
These and other matters have presented challenges to lubrication with bearing cages, for a variety of applications.